13bd94003SHeinz Mauelshagen // SPDX-License-Identifier: GPL-2.0-only 21da177e4SLinus Torvalds /* 31da177e4SLinus Torvalds * Copyright (C) 2003 Sistina Software. 41da177e4SLinus Torvalds * Copyright (C) 2004 Red Hat, Inc. All rights reserved. 51da177e4SLinus Torvalds * 61da177e4SLinus Torvalds * Module Author: Heinz Mauelshagen 71da177e4SLinus Torvalds * 81da177e4SLinus Torvalds * This file is released under the GPL. 91da177e4SLinus Torvalds * 101da177e4SLinus Torvalds * Path selector registration. 111da177e4SLinus Torvalds */ 121da177e4SLinus Torvalds 13586e80e6SMikulas Patocka #include <linux/device-mapper.h> 14056075c7SPaul Gortmaker #include <linux/module.h> 15586e80e6SMikulas Patocka 161da177e4SLinus Torvalds #include "dm-path-selector.h" 171da177e4SLinus Torvalds 181da177e4SLinus Torvalds #include <linux/slab.h> 191da177e4SLinus Torvalds 201da177e4SLinus Torvalds struct ps_internal { 211da177e4SLinus Torvalds struct path_selector_type pst; 221da177e4SLinus Torvalds struct list_head list; 231da177e4SLinus Torvalds }; 241da177e4SLinus Torvalds 251da177e4SLinus Torvalds #define pst_to_psi(__pst) container_of((__pst), struct ps_internal, pst) 261da177e4SLinus Torvalds 271da177e4SLinus Torvalds static LIST_HEAD(_path_selectors); 281da177e4SLinus Torvalds static DECLARE_RWSEM(_ps_lock); 291da177e4SLinus Torvalds __find_path_selector_type(const char * name)305e198d94SAlasdair G Kergonstatic struct ps_internal *__find_path_selector_type(const char *name) 311da177e4SLinus Torvalds { 321da177e4SLinus Torvalds struct ps_internal *psi; 331da177e4SLinus Torvalds 341da177e4SLinus Torvalds list_for_each_entry(psi, &_path_selectors, list) { 351da177e4SLinus Torvalds if (!strcmp(name, psi->pst.name)) 361da177e4SLinus Torvalds return psi; 371da177e4SLinus Torvalds } 381da177e4SLinus Torvalds 391da177e4SLinus Torvalds return NULL; 401da177e4SLinus Torvalds } 411da177e4SLinus Torvalds get_path_selector(const char * name)421da177e4SLinus Torvaldsstatic struct ps_internal *get_path_selector(const char *name) 431da177e4SLinus Torvalds { 441da177e4SLinus Torvalds struct ps_internal *psi; 451da177e4SLinus Torvalds 461da177e4SLinus Torvalds down_read(&_ps_lock); 471da177e4SLinus Torvalds psi = __find_path_selector_type(name); 48aea90588SJun'ichi Nomura if (psi && !try_module_get(psi->pst.module)) 491da177e4SLinus Torvalds psi = NULL; 501da177e4SLinus Torvalds up_read(&_ps_lock); 511da177e4SLinus Torvalds 521da177e4SLinus Torvalds return psi; 531da177e4SLinus Torvalds } 541da177e4SLinus Torvalds dm_get_path_selector(const char * name)551da177e4SLinus Torvaldsstruct path_selector_type *dm_get_path_selector(const char *name) 561da177e4SLinus Torvalds { 571da177e4SLinus Torvalds struct ps_internal *psi; 581da177e4SLinus Torvalds 591da177e4SLinus Torvalds if (!name) 601da177e4SLinus Torvalds return NULL; 611da177e4SLinus Torvalds 621da177e4SLinus Torvalds psi = get_path_selector(name); 631da177e4SLinus Torvalds if (!psi) { 641da177e4SLinus Torvalds request_module("dm-%s", name); 651da177e4SLinus Torvalds psi = get_path_selector(name); 661da177e4SLinus Torvalds } 671da177e4SLinus Torvalds 681da177e4SLinus Torvalds return psi ? &psi->pst : NULL; 691da177e4SLinus Torvalds } 701da177e4SLinus Torvalds dm_put_path_selector(struct path_selector_type * pst)711da177e4SLinus Torvaldsvoid dm_put_path_selector(struct path_selector_type *pst) 721da177e4SLinus Torvalds { 731da177e4SLinus Torvalds struct ps_internal *psi; 741da177e4SLinus Torvalds 751da177e4SLinus Torvalds if (!pst) 761da177e4SLinus Torvalds return; 771da177e4SLinus Torvalds 781da177e4SLinus Torvalds down_read(&_ps_lock); 791da177e4SLinus Torvalds psi = __find_path_selector_type(pst->name); 801da177e4SLinus Torvalds if (!psi) 811da177e4SLinus Torvalds goto out; 821da177e4SLinus Torvalds 831da177e4SLinus Torvalds module_put(psi->pst.module); 841da177e4SLinus Torvalds out: 851da177e4SLinus Torvalds up_read(&_ps_lock); 861da177e4SLinus Torvalds } 871da177e4SLinus Torvalds _alloc_path_selector(struct path_selector_type * pst)881da177e4SLinus Torvaldsstatic struct ps_internal *_alloc_path_selector(struct path_selector_type *pst) 891da177e4SLinus Torvalds { 90094262dbSDmitry Monakhov struct ps_internal *psi = kzalloc(sizeof(*psi), GFP_KERNEL); 911da177e4SLinus Torvalds 92094262dbSDmitry Monakhov if (psi) 931da177e4SLinus Torvalds psi->pst = *pst; 941da177e4SLinus Torvalds 951da177e4SLinus Torvalds return psi; 961da177e4SLinus Torvalds } 971da177e4SLinus Torvalds dm_register_path_selector(struct path_selector_type * pst)981da177e4SLinus Torvaldsint dm_register_path_selector(struct path_selector_type *pst) 991da177e4SLinus Torvalds { 1001da177e4SLinus Torvalds int r = 0; 1011da177e4SLinus Torvalds struct ps_internal *psi = _alloc_path_selector(pst); 1021da177e4SLinus Torvalds 1031da177e4SLinus Torvalds if (!psi) 1041da177e4SLinus Torvalds return -ENOMEM; 1051da177e4SLinus Torvalds 1061da177e4SLinus Torvalds down_write(&_ps_lock); 1071da177e4SLinus Torvalds 1081da177e4SLinus Torvalds if (__find_path_selector_type(pst->name)) { 1091da177e4SLinus Torvalds kfree(psi); 1101da177e4SLinus Torvalds r = -EEXIST; 1111da177e4SLinus Torvalds } else 1121da177e4SLinus Torvalds list_add(&psi->list, &_path_selectors); 1131da177e4SLinus Torvalds 1141da177e4SLinus Torvalds up_write(&_ps_lock); 1151da177e4SLinus Torvalds 1161da177e4SLinus Torvalds return r; 1171da177e4SLinus Torvalds } 118*aa07f9d8SHeinz Mauelshagen EXPORT_SYMBOL_GPL(dm_register_path_selector); 1191da177e4SLinus Torvalds dm_unregister_path_selector(struct path_selector_type * pst)1201da177e4SLinus Torvaldsint dm_unregister_path_selector(struct path_selector_type *pst) 1211da177e4SLinus Torvalds { 1221da177e4SLinus Torvalds struct ps_internal *psi; 1231da177e4SLinus Torvalds 1241da177e4SLinus Torvalds down_write(&_ps_lock); 1251da177e4SLinus Torvalds 1261da177e4SLinus Torvalds psi = __find_path_selector_type(pst->name); 1271da177e4SLinus Torvalds if (!psi) { 1281da177e4SLinus Torvalds up_write(&_ps_lock); 1291da177e4SLinus Torvalds return -EINVAL; 1301da177e4SLinus Torvalds } 1311da177e4SLinus Torvalds 1321da177e4SLinus Torvalds list_del(&psi->list); 1331da177e4SLinus Torvalds 1341da177e4SLinus Torvalds up_write(&_ps_lock); 1351da177e4SLinus Torvalds 1361da177e4SLinus Torvalds kfree(psi); 1371da177e4SLinus Torvalds 1381da177e4SLinus Torvalds return 0; 1391da177e4SLinus Torvalds } 1401da177e4SLinus Torvalds EXPORT_SYMBOL_GPL(dm_unregister_path_selector); 141